Answer:
The Manifest Destiny was the idea that the United States of America were destined, by divine right, to dominate all the stretch of land, from the Atlantic Ocean, to the Pacific. This idea was endorsed by former presidents such as Abraham Lincoln and Ulysses S. Grant.
The Oregon Trail was a long-widing road that crossed the United States, from the Great Plains, to the Pacific Ocean. Thousands of immigrants crossed the trail in the nineteenth century to settle new lands accross the west.
Because these settlers where establishing new farms, towns and cities western areas, they were fulfulling the Manifest Destiny idea that the United States should dominate all of these regions.